Real-time micro-vibration measurement with laser phase modulation

Abstract

Measurement accuracy is the most important criterion for laser distance measurement. The measurement accuracy can only reach half wavelength with the laser pulse method or laser interferometer. In this paper, a micro vibration detection method is proposed with laser phase modulation, whose measurement accuracy could reach 0.0179 wavelength. And it will have a better anti-interference ability to transmit signal with 40 MHz carrier. As verified by theoretical analysis, ESG simulation and the actual laser measurement experiments, the proposed measurement method with laser phase modulation can not only meet the real-time demand, but also improve the measurement accuracy.